The present invention relates to disc drive data storage devices. In particular, the present invention relates to testing of a simulated read/write head for disc drive data storage devices.
The condition or quality of an air bearing surface of a read/write head is important to the performance and life expectancy of the head. In particular, contamination of the surface that results in reduced electrical isolation between a magnetoresistive sensor and a magnetic shield can degrade head performance. Known methods for contamination testing include obtaining electron microphotographs of the air bearing surface or measuring electrical isolation using a hand probe to contact the magnetic shield. Electron microphotographs do not reliably predict electrical isolation and hand probing becomes increasingly difficult as the dimensions of the shield have become smaller and harder to contact with a hand probe.
An apparatus and method are needed for conveniently measuring the electrical isolation between a magnetoresistive sensor and a magnetic shield on a read/write head for a disc drive.
Disclosed are a test simulation circuit and a method of forming such a circuit. The test simulation circuit includes a simulated read/write head having a magnet shield and a magnetoresistive sensor that are exposed at a lapped surface of the simulated read/write head. The test simulation circuit includes a first electrical test path including a first bonding pad and a first internal connection connected to the magnetoresistive sensor. The test simulation circuit also includes a second electrical test path including a second bonding pad and a second internal connection connected to the magnet shield, the second electrical test path being electrically isolated from the first electrical test path.
Electrical isolation at the lapped surface can be tested using the first and second electrical test paths. Hand probing the lapped surface can be avoided. Electrical isolation testing can be performed while the lapped surface is being lapped. Additional features and benefits will become apparent with a careful review of the following drawings and the corresponding detailed description.